Thank you for using the Support Forum. I don't have that informtion you will need to contact your technician to get information on how to turn off the ECM and change the fax speed.
I've found it:
ECM Ability: 825-159 (1 Enable 0 Disable)
Reducing the transmitting or receiving baud rate from 33.6K bps to 14.4K or 9600 bps by changing NVM locations:
NVM Values: 1 = 33,600 9 = 14,400 11 = 9600